用指针函数实现最快最简单的按键控制程序。

// 按键的四种不同工作状态对应的函数指针对照表，每三字节对应一个按键

// 每一项包含三个字节，分别代表按键码，键盘状态，对应处理程序编号

// 本表对应于日常操作，不是修改状态-function pointer to achieve the quickest and most simple keypad control procedures. / / Button four different working conditions corresponding to the function pointer comparison table every three bytes for each keystroke / / Each one contains 3 bytes, representing key code, keyboard state, No. counterparts processing / / this table corresponds to the day-to-day operations, not the state